This invention relates to a high speed reproduction controlling method and apparatus which are particularly suitable for high speed reproduction control of a tape recorder which records or reproduces information by helically tracks on a tape using two rotary heads.
A home video tape recorder (to be referred to as a VTR hereinafter) adopting the recording/reproduction system described above has a high speed reproduction unit. In order to search a desired portion of a magnetic tape, the unit drives the tape at a speed several times to 20 times that used during recording.
There is a strong demand from users that a plurality of speeds be available or that search speed be variable, in order to allow easy search.
In order to provide this capability, however, a servo circuit for controlling the capstan for driving the tape must be arranged for each speed to be set. In addition, a correction circuit must be included for each different speed to correct deviations in horizontal frequency. Such deviations are caused by a large difference in relative speed beween the tape and the head in the recording and reproduction modes. Incorporation of the servo and correction circuits results in complexity for the entire VTR unit. In the high speed reproduction mode, since the head traces across tracks, noise bars are generated on the TV screen for displaying reproduced signals. There has been a strong demand for fixing the positions of these noise bars on the screen. In addition, then, a circuit for fixing the positions of the noise bars is required for each speed.
In the high speed reproduction unit of a VTR of the above type, the circuit configuration is complex and the number of adjustment locations is increased. As a result, the number of manufacturing steps is increased, and reliability suffers.